A young man using a smartphone in bed. Banning technology in the bedroom is one tip from sleep expert Vicki Culpin.
Photograph: amenic181/Getty Images

Britain is suffering an epidemic of sleeplessness, according to a book that takes a forensic look at the physical and mental consequences of failing to get a good night’s rest.

In The Business of Sleep, Prof Vicki Culpin, a clinical psychologist and expert in sleep and memory, warns: “Never before have significant percentages of working adults been so sleep deprived.”

Her book takes aim at “an age of foolishness” in which large numbers of people seem unaware of what Culpin describes as the “serious cognitive and health consequences of insufficient or poor quality sleep… despite the addition of sleep hygiene courses in corporate wellbeing and occupational health packages”.

High levels of sleeplessness expose people to risks ranging from the common cold to depression, dementia and a possible stroke or heart attack. The risk of obesity, cancer and diabetes is also increased.

Anyone who gets less then seven hours rest a night is at heightened risk of damage to their physical or mental health.

Exact numbers are hard to quantify but evidence suggests that large numbers of Britons get less sleep than they need. Research by the Royal Society for Public Health in 2016 found that we typically sleep for 6.8 hours a night. But a five-country study in 2013 by the National Sleep Foundation in America found that 16% of adults in the UK sleep for fewer than six hours a night while another 19% sleep for between six and seven hours.

Vicki Culpin, who says people are unaware of the health consequences of insufficient sleep

Sleeplessness carries an economic cost too, writes Culpin, who is professor of organisational behaviour at Ashridge Executive Education, part of Hult International Business School. The UK loses 200,000 working days a year to absenteeism caused by lack of sleep. “Getting the right amount of sleep every night can reduce mortality, improve organisational effectiveness and save the UK economy between $36.7bn and $50bn (1.36%-1.86% of GDP) every year,” she says

Culpin also details how regularly sleeping too much – more than nine hours a night – may also have an impact on health. Poor sleep also affects our memory, decision-making, creativity and mood.

According to The Business of Sleep, jetlag, alcohol, exercise, caffeine, noise, young children, shift work, late night carousing and use of electronic media all help explain the epidemic. But Culpin identifies a key culprit as “the macho attitudes of organisations that focus on presenteeism and the long-hours culture as a badge of honour”. She hopes her book, which is aimed at business people, will be “a wake-up call. There is a very clear imperative to make changes.”

Culpin’s tips for ensuring good sleep include avoiding heavy or spicy food for two to three hours before bedtime, using blackout blinds to make your bedroom darker or an eyemask, avoiding naps after 5pm and establishing a regular wind-down routine, including going to bed at roughly the same time every night, including at weekends, and having no technology in the bedroom.

Dr Mike Farquhar, a sleep expert and paediatrician at the Evelina Children’s Hospital in London, says that too many Britons do not prioritise sleep. “All of us can come up with lots of ways to spend our time that feel ‘better’ to us than getting a good night’s sleep, and we don’t emphasise enough just how important getting the right amount of sleep is to our physical and mental health and wellbeing and our ability to function at work.

“I worry that so many people still don’t understand how much benefit there is to making sure they have a good sleep routine that gives them the right amount of sleep for them, most nights of their life, and what the consequences to their long-term health might be.

The Business of Sleep by Vicki Culpin is published by Bloomsbury on 8 March